When new words and terminology enter our vernacular, they often take on a connotation larger and broader than they deserve.Today, “green” and “sustainable” are synonymous with responsible living and construction, their meanings understood as clearly by an architect or engineer as they are by the lay person.They are buzz words that make consumers feel good about their purchases; they’re doing their part to protect the environment and help save the world.But, in certain applications, use of these terms is more than a misnomer; it’s outright false advertising.

Technological advances in building science have allowed for the creation of the most energy efficient systems and materials that the construction industry has ever seen.With the ever rising cost of every fuel type, energy conservation is always a high priority when planning for and designing buildings.Buildings, historically, are only as efficient as the technology of the day allowed.While we may shudder with the chill of a stiff breeze standing by the window in an 1885 Queen Anne Victorian, imagine the relative level of comfort that one of the Pilgrims would have enjoyed in the same situation!Today’s building designers want to create watertight, airtight structures that use minimal amounts of energy with windows sealed tight and year-round climate control for maximum comfort.They strive to design an envelope that needs low or no maintenance, fully accepting that building owners will not care for their buildings as a given.As far as new construction goes, there’s no problem.In fact, this is good news.But what happens when the owners of older buildings want to implement these new technologies to increase the efficiency of their buildings?Older building stock tends to be far less efficient than modern buildings.Wall systems and joinery, windows and doors—they’re just not as tight. An unexpected benefit of these inefficiencies is the passive ventilation that occurs, be it laterally through windows, doors and walls, or by the “stack effect” in which warm air rises, bringing vapor with it, escaping through the uninsulated roof system.Know this: older buildings breath.Modern building systems are designed so that structures don’t breath and vapor is removed with dehumidifiers or other mechanical forms of ventilation.In older buildings, solid masonry walls rely on the temperature gradient between interior conditioned spaces and the outside for walls to drain properly.Insulating these walls stops or mitigates the passage heat through the solid brick masonry.This slows the drainage/drying process and traps moisture vapor in the wall which, during freeze-thaw cycles, freezes and expands up to 12% in volume.Oftentimes the result is damage to the wall system of the envelope.Instead, the focus should be on controlling moisture and preventing it from entering the wall system, both inside and out.Today, older buildings have kitchens, bathrooms and laundry spaces that they didn’t when first built.This introduces a significant amount of moisture vapor that may enter the wall system from the interior.Installation of a vapor barrier will prevent this from occurring without impacting the thermal effect that heated interior spaces have on the exterior walls.Outside, mortar joints must be kept tight and full.Penetrations such as window and door jambs must be sealed tight where they abut masonry to prevent water intrusion.Roof drainage systems must be functional; gutters protect and shed the walls from runoff and properly placed leaders direct the rainwater away from the building at grade.It’s also interesting to note that many older masonry buildings have large windows resulting in a high window opening-to-wall surface area ratio.Improving the efficiency of the fenestration through conservation and repair, as well as the addition of efficient interior or exterior storm windows, will help preserve the historic integrity of the building while also saving on energy costs.Recently a client contacted me with questions and concerns about insulating his masonry walls.He was engaged in gutting much of the interior space in his circa 1870 brick townhouse in a National Register historic district in Boston’s South End.The building department was demanding that he insulate behind the walls in compliance with the International Energy Conservation Code.When we pointed out that the code specifically exempts buildings on or eligible for inclusion on state or national historic registers, he said it didn’t matter if there was a lot of interior gutting; that was his interpretation of the code.Only later, when a staff member from the Boston Landmarks Commission intervened, was he straightened out.Before you breath a sigh of relief, owners may have to prove that their historic projects are worthy of exemptions from the International Energy Conservation Code following changes to the forthcoming 2015 version approved by the International Code Council last year. The changes were proposed by representatives from the New Buildings Institute, the Natural Resources Defense Council and the Institute for Market Transformation and they remove the exemption language from the code. The group added a requirement that permit applicants file a report with a code official when seeking immunity on specific areas of their project.Do they sound like groups that know about old buildings?No, they don’t.They sound like groups that think LEED certification matters when it comes to old buildings; you know, organizations that don’t think full life cycle analysis matters in “green” building practices.Why wouldn’t the team include representatives from the Association for Preservation Technology or the Preservation Trades Network?And, frighteningly, who will train the code official that decides whether a project receives an exemption or not?The answer is NOBODY.So guess what happens when you encounter our friend in Boston?More and more I’m coming to believe that these people actually hate old buildings.I’ve had arguments with architects and contractors who wanted to spray closed-cell foam insulation between the rafters under slate roofs.Some specified removing all the slate and covering the roof with an ice and water shield membrane then reinstalling the slate, effectively “sealing” the roof tight.Besides being an unnecessary, exorbitant extra cost, there’s a big problem with these grand, USGBC-inspired plans:they actually destroy the materials in a traditional roofing system.Slate, clay tiles and wood shingles are traditionally fastened to battens, skip sheathing or regular old boards—not plywood, no underlayments.The roofs are water tight, not air tight and the building breaths through the roof.Fiberglass insulation can improve energy efficiency and reduce heat loss without preventing the roof from breathing.Additionally, soffit and ridge ventilation can be added if desired.Traditional roof materials like slate, clay tile and cedar shingles experience condensation.The passage of vapor helps dry things out.When you stop the roof from breathing everything stays wet.Slate is comprised of thin layers of metamorphic rock that delaminate and fall apart when they are kept damp for months.Clay tiles, like terra cotta and brick, will disintegrate.Wood shingles rot.Steel fasteners will experience corrosion and fail.This has been the end of many a slate roof; I’ve pulled the slates off the roof and seen it with my own eyes.Cedar shingle roofs will last five years, max, when installed on a solid roof deck covered in ice and water shield.The reality is this: greener is not always better, especially when wielded by those unfamiliar with traditional building systems.“The greenest building is the one already there” is a common expression in the historic preservation world yet it’s never heard in “green building” circles. Go figure.

Ward... all very good points! I cringe when I see the new energy code that does NOT allow exemptions for historic buildings. For that matter, any solid masonry building (like the one I'm working with now constructed in 1913) that is NOT designated "historic" will not qualify for exemptions from the energy code, so I am pushing for establishing it's historic status with our State Historic Preservation Office so that we can not only get the exemption from insulating the exterior walls, but to also take advantage of rehabilitation tax credits. With regard to solid masonry buildings, insulation on the exterior walls will prove to be a disaster as you've described simply because they do not have a "cavity" like modern buildings have which can shed water and allow for insulation in a modern way.

How do we get our states (NY, MA and others) to amend the energy code when they adopt it to not only keep the exemption in for historic buildings, but to exempt all solid masonry structures from being insulated??!!

I'm not sure. In Massachusetts, we are operating under IECC 2009 until July 1st, 2014, when IECC 2012 kicks in. Rather than wait for IECC 2015 to become code and lobby the states to amend that part, I would favor a pre-emptive strike. This is the time when groups and committees under the Code Council are meeting and drafting proposed changes, like elimination of the historic building exemption. In Massachusetts, the State Board of Building Regulations and Standards (BBRS) has to approve and adopt the new code for it to become "law." I believe that NOW is the time when Preservation Massachusetts should be joining forces with the Mass Historical Commission and going on the offensive. MHC can meet with the BBRS and advise as to what the potential problems are with the proposed change. The BBRS can then contact the Codes Council and alert the to the concerns. If this happened in a dozen key states, with the National Trust coordinating efforts, I imagine the Codes Council would revisit the issue.

The other part that scared me was: "The group added a requirement that project teams file a report with a code official when seeking immunity on specific areas of the design or construction." Holy mackerel, the fate of the building will lie in the code official's hands? What training will they be given? NONE. So how can they make a qualified judgment?

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About the author

Ward Hamilton is a recognized expert in historic preservation and the owner of Olde Mohawk Historic Preservation. He provides consulting and contracting services to clients in Greater Boston and throughout New England.

Olde Mohawk provides historic preservation consulting and contracting services for clients in Boston and throughout New England and has worked on several dozen buildings listed on the National Register of Historic Places.